AMERICAN THYROID ASSOCIATION® www.thyroid.org Goiter WHAT IS THE THYROID GLAND? Hashimoto’s thyroiditis is a more common cause of goiter formation in the US. This is an autoimmune condition The thyroid gland is a butterfly-shaped endocrine gland in which there is destruction of the thyroid gland by that is normally located in the lower front of the neck. one’s own immune system. As the gland becomes more The thyroid’s job is to make thyroid hormones, which damaged, it is less able to make adequate supplies of are secreted into the blood and then carried to every thyroid hormone. The pituitary gland senses a low thyroid tissue in the body. Thyroid hormones help the body use hormone level and secretes more TSH to stimulate the energy, stay warm and keep the brain, heart, muscles, thyroid. This stimulation causes the thyroid to grow, and other organs working as they should. which may produce a goiter. WHAT ARE THE SYMPTOMS OF A GOITER? Another common cause of goiter is Graves’ disease. The term “goiter” simply refers to the abnormal enlarge In this case, one’s immune system produces a protein, ment of the thyroid gland. It is important to know that called thyroid stimulating immunoglobulin (TSI). As the presence of a goiter does not necessarily mean that with TSH, TSI stimulates the thyroid gland to enlarge the thyroid gland is malfunctioning. A goiter can occur producing a goiter. However, TSI also stimulates the in a gland that is producing too much hormone (hy thyroid to make too much thyroid hormone (causes perthyroidism), too little hormone (hypothyroidism), or hyperthyroidism). Since the pituitary senses too much the correct amount of hormone (euthyroidism). A goiter thyroid hormone, it stops secreting TSH. In spite of this indicates there is a condition present which is causing the thyroid gland continues to grow and make thyroid the thyroid to grow abnormally. hormone. Therefore, Graves’ disease produces a goiter and hyperthyroidism. WHAT CAUSES A GOITER? Multinodular goiters are another common cause of One of the most common causes of goiter formation goiters. Individuals with this disorder have one or worldwide is iodine deficiency. While this was a very more nodules within the gland which cause thyroid frequent cause of goiter in the United States many enlargement. This is often detected as a nodular feeling years ago, it is no longer commonly observed. The gland on physical exam. Patients can present with a primary activity of the thyroid gland is to concentrate single large nodule or with multiple smaller nodules in the iodine from the blood to make thyroid hormone. The gland when first detected (see Thyroid Nodule brochure). gland cannot make enough thyroid hormone if it Thus, in early stages of a multinodular goiter with many does not have enough iodine. Therefore, with iodine small nodules, the overall size of the thyroid may not be deficiency the individual will become hypothyroid. enlarged yet. Unlike the other goiters discussed, the Consequently, the pituitary gland in the brain senses cause of this type of goiter is not well understood. the thyroid hormone level is too low and sends a signal In addition to the common causes of goiter, there are to the thyroid. This signal is called thyroid stimulating many other less common causes. Some of these are hormone (TSH). As the name implies, this hormone due to genetic defects, others are related to injury or stimulates the thyroid to produce thyroid hormone and infections in the thyroid, and some are due to tumors to grow in size. This abnormal growth in size produces (both cancerous and benign tumors). what is termed a “goiter.” Thus, iodine deficiency is one cause of goiter development. Wherever iodine deficiency is common, goiter will be common. It remains a common cause of goiters in other parts of the world.
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HOW DO YOU DIAGNOSE A GOITER? HOW IS A GOITER TREATED? As mentioned earlier, the diagnosis of a goiter is usually The treatment will depend upon the cause of the goiter. If made at the time of a physical examination when an the goiter was due to a deficiency of iodine in the diet (not enlargement of the thyroid is found. However, the common in the United States), you will be given iodine presence of a goiter indicates there is an abnormality of supplementation given in preparations to take by mouth. the thyroid gland. Therefore, it is important to determine This will lead to a reduction in the size of the goiter, but the cause of the goiter. As a first step, you will likely often the goiter will not completely resolve. have thyroid function tests to determine if your thyroid If the goiter is due to Hashimoto’s Thyroiditis, and you is underactive or overactive (see Thyroid Function Tests are hypothyroid, you will be given thyroid hormone brochure). Any subsequent tests performed will be supplement as a daily pill. This treatment will restore your dependent upon the results of the thyroid function tests. If thyroid hormone levels to normal, but does not usually the thyroid is diffusely enlarged and you are hyperthyroid, make the goiter go completely away. While the goiter may your doctor will likely proceed with tests to help diagnose get smaller, sometimes there is too much scar tissue in Graves’ Disease (see Graves’ Disease brochure). the gland to allow it to get much smaller. However, thyroid If you are hypothyroid, you may have Hashimoto’s hormone treatment will usually prevent it from getting any Thyroiditis (see Hypothyroidism brochure) and you may larger. Although appropriate in some individuals, surgery get additional blood tests to confirm this diagnosis. is usually not routine treatment of thyroiditis. Other tests used to help diagnose the cause of the If the goiter is due to hyperthyroidism, the treatment will goiter may include a radioactive iodine scan, thyroid depend upon the cause of the hyperthyroidism (see ultrasound, or a fine needle aspiration biopsy (see Hyperthyroidism and Graves’ disease brochures). For Thyroid Nodule brochure). some causes of hyperthyroidism, the treatment may lead to a disappearance of the goiter. For example, treatment of Graves’ disease with radioactive iodine usually leads to a decrease or disappearance of the goiter. Many goiters, such as the multinodular goiter, are associated with normal levels of thyroid hormone in the blood. These goiters usually do not require any specific treatment after the appropriate diagnosis is made. If no specific treatment is suggested, you may be warned that you are at risk for becoming hypothyroid or hyperthyroid in the future. However, if there are problems associated with the size of the thyroid per se, such as the goiter getting so large that it constricts the airway, your doctor may suggest that the goiter be treated by surgical removal. Whatever the cause, it is important to have regular (annual) monitoring when diagnosed with a goiter.
FURTHER INFORMATION Further details on this and other thyroid-related topics are available in the patient thyroid ® This page and its contents information section on the American Thyroid Association website at www.thyroid.org. are Copyright © 2019 2 the American Thyroid Association® For information on thyroid patient support organizations, please visit the Patient Support Links section on the ATA website at www.thyroid.org